Fix DLL export for NblExt*

Author: deprilula28

cmake/common.cmake

@@ -238,6 +238,7 @@ macro(nbl_create_ext_library_project EXT_NAME LIB_HEADERS LIB_SOURCES LIB_INCLUD
 	target_link_libraries(${LIB_NAME} PUBLIC Nabla)
 	target_compile_options(${LIB_NAME} PUBLIC ${LIB_OPTIONS})
 	target_compile_definitions(${LIB_NAME} PUBLIC ${DEF_OPTIONS})
+	target_compile_definitions(${LIB_NAME} PRIVATE __NBL_BUILDING_NABLA__)
 	set_target_properties(${LIB_NAME} PROPERTIES MSVC_RUNTIME_LIBRARY "MultiThreaded$<$<CONFIG:Debug>:Debug>")
 
 	if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "GNU")

include/nbl/ext/ImGui/ImGui.h

@@ -1,12 +1,13 @@
 #ifndef NBL_EXT_IMGUI_UI_H
 #define NBL_EXT_IMGUI_UI_H
 
+
 namespace nbl::ext::imgui
 {
 	class NBL_API2 UI final : public core::IReferenceCounted{
 	public:
 
-		explicit UI(
+		UI(
 			core::smart_refctd_ptr<video::ILogicalDevice> device,
 			int maxFramesInFlight,
 			core::smart_refctd_ptr<video::IGPURenderpass>& renderPass,